threshold stimulus

Concentric contractions

Eccentric Contractions

Muscle Tone

The state of partial contraction in a muscle, even when the muscle is not being used. Muscle tone does not produce active movements, but it keeps muscles firm, healthy and ready to respond to any situation

myasthenia gravis

Fibromyositis

Also known as fibromyalgia. A group of conditions involving chronic inflammation of a muscle, its connective tissue coverings and tendon, and capsules of nearby joints. Symptoms are nonspecific and involve varying degrees of tenderness, as well as fatigue and sleeplessness.

Hernia

Protrusion of an organ through its body cavity wall. May be congenital (owing to failure of muscle fusion during development), but most often is caused by heavy lifting or obesity and subsequent muscle weakening.

Myofascial pain syndrome

Myopathy

Myostonic Dystrophy

A form of muscular dystrophy that is less common than DMD; in the US it affects about 14 of 100K ppl. Symptoms include a gradual reduction in muscle mass and control of the skeletal muscles, abnormal heart rhythm, and diabetes mellitus. May appear at any time; not sex-linked. Underlying genetic defect is multiple repeats of a gene on chromosome 19. Repeats increase each generation. Subsequent generations develop more severe symptoms. No effective treatment.

RICE

Spasm

A sudden, involuntary twitch in smooth or skeletal muscle ranging from merely irritating to very painful. May be due to chemical imbalances. In spasms of eyelid or facial muscles, called ticks, psychological factors may be involved. Stretching and massaging may help. A cramp is a prolonged spasm, usually occurs at night or after exercise.

Strain

Commonly called a "pulled muscle." A strain is excessive stretching and possible tearing of a muscle due to muscle overuse or abuse. The injured muscle becomes painfully inflamed (myositis) and adjacent joints are usually immobilized.

Tetanus

(1) A state of strained contraction of a muscle that is a normal aspect of skeletal muscle functioning. (2) An acute infectious disease caused by the anaerobic bacterium Clostridium tetani and resulting in painful spasms of some skeletal muscles. Progresses to fixed rigidity of the jaws (lockjaw) and spasms of trunk and limb muscles. Usually fatal due to respiratory failure.

pennate muscle

Charley horse

a muscle contusion. ie. tearing of muscle followed by bleeding into the tissue (hematoma) and severe, prolonged pain. A common contact sport injury; football players frequently suffer a charley horse of the quadriceps (muscle of the thigh)

Electromyography

Recording and interpretation of graphic records of the electrical activity of contracting muscles. Electrodes inserted into the muscles record the impulses that pass over muscle-cell membranes to stimulate contraction.

Hernia

An abnormal protrusion of abdominal contents (typically coils of the small intestine) through a weak point in the muscles of the abdominal wall. Most often caused by increased intraabdominal pressure during lifting or straining. The hernia penetrates the muscle wall, but not the skin and so appears as a visible bulge in the body surface. Common abdominal hernias include the inguinal and umbilical hernias.

Quadriceps and hamstring strains

Also called quad and hamstring pulls, these conditions involve tearing these muscles or their tendons; happen mainly in athletes who do not warm up properly and then fully extend their hip (qad pulls) or knee (hamstring pull) quickly or forcefully (e.g., sprinters, tennis players). Not painful at first, but pain intensifies within three to six hours (30 minutes if the tearing is severe). After a week of rest, stretching is the best therapy

Ruptured calcaneal tendon

Although the calcaneal (achilles) tendon is the largest, strongest tendon in the body, its rupture is surprisingly common, particularly in older people as a result of stumbling and in young sprinters when the tendon is traumatized during takeoff. The rupture is followed by abrupt pain; a gap is seen just above the heel, and the calf bulges as the triceps surae are released from their insertion. Plantar flexion is weak or impossible, but dorsiflexion is exaggerated. Usually repaired surgically.

Shin splints

Common term for pain in the anterior compartment of the leg caused by irritation of the tibialis anterior muscle as might follow extreme or unusual exercise without adequate prior conditioning. Because it is tightly wrapped by fascia, the inflamed tibialis anterior cuts off its own circulation as it swells and presses painfully on its own nerves.

Tennis elbow

Tenderness due to trauma or overuse of the tendon of origin or the forearm extensor muscles at the lateral epicondyle of the humerus. Caused and aggravated when these muscles contract forcefully to extend the and at the wrist--as in executing a tennis backhand or lifting a loaded snow shovel. Despite its name, tennis elbow does not involve the elbow joint; most cases caused by work activities.

Torticollis

A twisting of the neck in which there is a chronic rotation and tilting of the head to one side, due to injury of the sternocleidomastoid muscle on one side; also called wryneck. Sometimes present at birth when muscle fibers are torn during difficult delivery. Exercise that stretches the affected muscle is the usual treatment.